Reinforced fused-deposition modeling

ABSTRACT

An apparatus for manufacturing an object includes an extrusion head having an extrusion needle for extruding thermoplastic material associated with one or more fiber strands. The apparatus may further include a turn-table, a more robotic arm for moving the extrusion head and needle, thermoplastic filament and fiber strand spools and thermoplastic filament and fiber strands. A controller is provided for directing the robotic arm, extrusion head and the turn-table. Further, a method for manufacturing an object includes generating a design for the object that substantially satisfies desired structural properties of the object and generating a sequence for extruding one or more beads of thermoplastic material to manufacture the object according to the design, in which the one or more beads of thermoplastic material are associated with one or more fiber strands. The one or more beads of thermoplastic material and the associated one or more fiber strands are then extruded according to the sequence.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/766,376, filed Feb. 19, 2013, entitled “REINFORCED FUSED-DEPOSITION MODELING” (Attorney Docket 3019-001PR1), which is incorporated herein by reference. If there are any contradictions or inconsistencies in language between this application and the case that has been incorporated by reference that might affect the interpretation of the claims in this case, the claims in this case should be interpreted to be consistent with the language in this case.

FIELD

The present disclosure relates to manufacturing, and, more particularly, to fused-deposition modeling.

BACKGROUND

Fused-deposition modeling is a technique for building a three-dimensional object from a mathematical model of the object. In general, the object is built by feeding a thermoplastic filament into a heated extrusion head. The heated extrusion head melts and deposits the molten thermoplastic material as a series of beads. Each bead is roughly spherical or cylindrical in shape—and is much like the toothpaste that is squeezed from a tube—but much smaller than a grain of rice. Typically, a bead is between 0.001^(th) to 0.010^(th) of an inch thick. When a bead is deposited, it is just slightly above its melting point. After it is deposited, the bead quickly solidifies and fuses with the beads that are next to and below it.

Perhaps the greatest advantage of fused-deposition modeling is that it can build an object of any shape. To accomplish this, however, there are constraints on the sequence in which the beads can be deposited. First, each bead must be supported. In other words, a bead cannot be deposited on air. Therefore, each bead must be deposited on:

-   -   (i) a platform that is not part of the object, or     -   (ii) one or more previously-deposited beads that will be part of         the object, or     -   (iii) a temporary scaffold of support material that is not part         of the object, or     -   (iv) any combination of i, ii, and iii.         Second, when a three-dimensional surface is sealed with beads,         it is no longer possible to deposit a bead inside of that         surface. This is analogous to the situation in which once you         close a box, you can't put anything into the box.

There is a general methodology that is used in fused-deposition modeling that satisfies these constraints and enables the building of an object of any shape. The three-dimensional model of the object is modeled as thousands of thin layers in the X-Y plane. Each layer is modeled as thousands of beads and voids. The object is then built, one bead at a time, one layer at a time, only in the +Z direction.

There are, however, costs and disadvantages associated with traditional fused-deposition modeling.

SUMMARY

One of the disadvantages of traditional fused-deposition modeling is that the resulting objects are not strong enough for many applications. That is why the objects are often used only as models or prototypes of “real” objects.

Embodiments of the present disclosure address this deficiency by combining fiber strands with fused-deposition modeling to create fiber-reinforced objects. In general, fiber-reinforced objects are much stronger than unreinforced objects.

A fiber-reinforced object is built by depositing one or more fiber strands in association with one or more beads of thermoplastic material. A fiber strand and a bead can be associated in which:

-   -   (i) the fiber strand is wholly within the bead, or     -   (ii) the fiber strand is partially within the bead, or     -   (iii) the fiber strand is adjacent to the bead, or     -   (iv) any combination of i, ii, and iii.         A fiber strand and an associated bead can be deposited together         or separately. The fiber strand can be deposited first and then         the bead can be deposited. Alternatively, the bead can be         deposited first and then the fiber strand can be deposited. One         fiber strand can be associated with one or more beads, and one         bead can be associated with one or more fiber strands.

The length of a fiber strand can be:

-   -   (i) “short,” or     -   (ii) “medium,” or     -   (iii) “long.”

A “short-length” fiber strand has a maximum length that is less than twice the minimum dimension of a bead. The angular orientation of the longitudinal or neutral axis of a short-length fiber strand associated with a bead is generally correlated with the longitudinal or neutral axis of the bead. Although the ends of a short-length fiber strand can extend beyond the wall of a bead—like a spine on a cactus—a short-length fiber strand intersects only one bead and its immediate neighbors. In accordance with some embodiments of the present disclosure, short-length fiber strands are cut before being deposited, but in other embodiments the short-length fiber strands are cut while being deposited.

A “long-length” fiber strand has a length that is approximately equal to the length of a bead. The angular orientation of a long-length fiber strand associated with a bead is generally parallel to the longitudinal or neutral axis of the bead. In accordance with some embodiments of the present disclosure, long-length fiber strands are cut while being deposited, but in other embodiments the long-length fiber strands are cut before being deposited.

A “medium-length” strand has a length longer than a short-length fiber strand and shorter than a long-length fiber strand. The angular orientation of a medium-length fiber strand associated with a bead is generally parallel to the longitudinal or neutral axis of the bead. In accordance with some embodiments of the present disclosure, short-length fiber strands are cut before being deposited, but in other embodiments the short-length fiber strands are cut while being deposited.

In accordance with embodiments of the present disclosure, a bead can be associated with a fiber strand made of glass, carbon, aramid, cotton, wool, or any other fibrous material.

A bead can be associated with one or more bundles of fiber strands. A bundle of fiber strands can be grouped as a tow, a yarn, or a braid. The cross section of a bundle of fiber strands can be flat, cylindrical, rectangular, triangular, or irregular. A bundle of fiber strands can comprise fiber strand made of one or more materials (e.g., glass and carbon, glass and aramid, carbon and aramid, glass and carbon and aramid, etc.).

An object that is built in accordance with present disclosure can comprise:

-   -   (i) beads that are not associated with a fiber strand, or     -   (ii) beads that are associated with “short” strands, or     -   (iii) beads that are associated with “medium” strands, or     -   (iv) beads that are associated with “long” strands, or     -   (v) any combination of i, ii, iii, and iv.

In accordance with some embodiments of the present disclosure, the thermoplastic filament comprises one or more fiber strands (or one or more bundles of fiber strands) prior to being fed into the extrusion head. In some alternative embodiments, one or more fiber strands (or one or more bundles of fiber strands) are combined with the thermoplastic material during deposition.

Some embodiments of the present disclosure comprise a plurality of thermoplastic filaments in which at least one of the filaments does not comprise a fiber strand and at least one of the filaments does comprise a fiber strand. Furthermore, some embodiments of the present disclosure comprise a plurality of thermoplastic filaments that each comprise:

-   -   (i) a fiber strand of different length, or     -   (ii) a fiber strand of different material, or     -   (iii) a fiber strand of different modulus, or     -   (iv) a different bundle of fiber strands, or     -   (v) any combination of i, ii, iii, and iv.

Some embodiments of the present disclosure can deposit multiple beads and fiber strands (or bundles of fiber strands) in parallel.

Some embodiments of the present disclosure can deposit:

-   -   (i) a bead of thermoplastic material, or     -   (ii) a fiber strand, or     -   (iii) both a bead of thermoplastic material and a fiber strand         in a substantially straight segment whose longitudinal or         neutral axis is:     -   (a) in the X-Y plane and parallel to the X axis, or     -   (b) in the X-Y plane and parallel to the Y axis, or     -   (c) in the X-Y plane and at an acute angle to the X axis, or     -   (d) at a right angle to the X-Y plane, or     -   (e) at an acute angle to the X-Y plane.

Some embodiments of the present disclosure can deposit:

-   -   (i) a bead of thermoplastic material, or     -   (ii) a fiber strand, or     -   (iii) both a bead of thermoplastic material and a fiber strand         in a two-dimensional curvilinear segment (e.g., an arc,         substantially a circle, a parabola, a sinewave, a spiral, a         cissoid, a Folium of Descartes, a planar spring, etc.) that lies         in a plane that is:     -   (a) parallel to the X-Y plane, or     -   (b) at a right angle to the X-Y plane, or     -   (c) at an acute angle to the X-Y plane.

Some embodiments of the present disclosure can deposit:

-   -   (i) a bead of thermoplastic material, or     -   (ii) a fiber strand, or     -   (iii) both a bead of thermoplastic material and a fiber strand         in a helical segment (e.g., a circular helix, a conical helix, a         cylindrical or general helix, a left-handed helix, a         right-handed helix, etc.) whose axis is:     -   (a) in the X-Y plane, or     -   (b) at a right angle to the X-Y plane, or     -   (c) at an acute angle to the X-Y plane.         The helix can be regular or irregular (like the windings of rope         on a spool).

Some embodiments of the present disclosure can deposit:

-   -   (i) a bead of thermoplastic material, or     -   (ii) a fiber strand, or     -   (iii) both a bead of thermoplastic material and a fiber strand         in a polygon (e.g., a triangle, a rectangle, etc.) that lies in         a plane that is:     -   (a) parallel to the X-Y plane, or     -   (b) at a right angle to the X-Y plane, or     -   (c) at an acute angle to the X-Y plane.         The polygon can be regular or irregular, simple or not simple,         concave or non-concave, convex or non-convex.

In general, some embodiments of the present disclosure can deposit beads of thermoplastic material and fiber strands in many topologies (e.g., a toroid, a cage, etc.).

The fact that some embodiments of the present disclosure can deposit a fiber strand at a non-zero angle to the X-Y plane can create a situation in which the general methodology of depositing beads in a strict layer-by-layer sequence are not possible. Therefore, some embodiments of the present disclosure generate an sequence for depositing the beads and fiber strands that is manufacturable. Such sequences can iteratively progress in both the +X, −X, +Y, −Y, +Z, and −Z directions.

The location of the fiber strands in the object and their geometry and orientation can affect the structural properties of the object. Furthermore, the structural properties of the object can be predicted based on the location of the fiber strands in the object and their geometry. Therefore, some embodiments of the present disclosure accept both a mathematical model of the object and a list of the desired structural properties of the object, and generate a design for:

-   -   (i) the number of fiber strands in the object, and     -   (ii) the bundling of the fiber strands in the object, and     -   (iii) the material of the fiber strands in the object, and     -   (iv) the Young's modulus of the fiber strands in the object, and     -   (v) the location of the fiber strands in the object, and     -   (vi) the geometry of the fiber strands in the object, and     -   (vii) the orientation of the fiber strands in the object, and     -   (viii)an sequence for depositing the beads and fiber strands         that:     -   (1) attempt to satisfy the desired structural properties of the         object, and     -   (2) can be actually be built.

The latter condition is especially important because there are many arrangements of fibers that cannot be manufactured using fused-deposition modeling.

Some embodiments of the present disclosure are capable of depositing support material at a location and removing the support material and re-depositing the support material at the same location and of removing the re-deposited support material. This is to enable the support of a bead and fiber strand at one moment and then after the bead has hardened to enable another bead and fiber strand to be deposited under the first.

Some embodiments of the present disclosure comprise a turntable that supports the object while it is built and that spins under the control of the embodiment's CAD/CAM controller. This facilitates the deposition of circular and helical beads and fiber strands on the object. This also facilitates the ability of the embodiments to deposit beads and fiber strands at any location in the build volume from any approach angle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a front view of manufacturing system 100 in accordance with the illustrative embodiment of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 depicts a front view of manufacturing system 100 in accordance with the illustrative embodiment of the present disclosure. Manufacturing system 100 may comprise:

-   -   CAD/CAM controller 101,     -   build chamber 102,     -   turn-table 110,     -   one or more robotic arms 121, each comprising an extrusion head         122 with an extrusion needle 123,     -   thermoplastic filament spool 130-1 and thermoplastic filament         131-1,     -   thermoplastic filament spool 130-2 and thermoplastic filament         131-2, and     -   fiber strand spool 130-3 and fiber strand 131-3.         The purpose of manufacturing system 100 is to build a         three-dimensional object—depicted as object 151 in FIG. 1.

CAD/CAM controller 101 directs the building of object 151 based on a mathematical model of object 151. In accordance with the illustrative embodiment, the mathematical model of object 151 is created with CAD/CAM controller 101, but it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present disclosure in which the model is created elsewhere and imported into CAD/CAM controller 101.

CAD/CAM controller 101 may comprise a list of the desired structural properties of object 151. This list may include, but is not limited to:

-   -   1. the desired compression strength characteristics of object         151, and     -   2. the desired tensile strength characteristics of object 151,         and     -   3. the desired resonance characteristics of object 151.

In accordance with the illustrative embodiment, thermoplastic filament 131-1 comprises a continuous tow of 5 low-modulus carbon-fiber strands, and thermoplastic filament 131-2 does not comprise a fiber strand. Thermoplastic filament 131-2 is used as support material in building object 151.

CAD/CAM controller 101 may also comprise a list of the structural properties of thermoplastic filament 131-1. This list may include, but is not limited to:

-   -   1. the compression strength of the thermoplastic and tow of         carbon fibers (after deposition and in object 151), and     -   2. the tensile strength of the thermoplastic and tow of carbon         fibers (after deposition and in object 151), and     -   3. the thermal expansion of the thermoplastic and tow of carbon         fibers (after deposition and in object 151), and     -   4. the Young's modulus of the thermoplastic and tow of carbon         fibers (after deposition and in object 151).

CAD/CAM controller 101 may also comprise a list of the structural properties of thermoplastic filament 131-2 and/or fiber strand 131-3.

CAD/CAM controller 101 generates a design for object 151 that:

-   -   (1) attempts to satisfy the desired structural properties of         object 151, and     -   (2) a sequence for depositing beads of thermoplastic material         and support material.         The design for object 151 includes, but is not limited to:     -   (i) the location of fiber strands in the object, and     -   (ii) the geometry of the fiber strands in the object.

Build chamber 102 is an enclosed environment in which object 151 is built.

Turn-table 110 comprises a platform on which object 151 is built. Turn-table 110 may be driven by a drive mechanism 110-1 that is directed by CAD/CAM controller 101. The drive mechanism 110-1 may comprise a motor arrangement including, but not limited to one or more stepper and/or servo motors. Some embodiments may also include a transmission or gear arrangement for controlled transmission of the rotational movement of the motor(s) to the turn-table 110. The transmission or gear arrangement may include without limitation one or more gears, belts, chains, and combinations thereof.

Various embodiments of the drive mechanism 110-1 may be configured to rotate the turn-table 110 in clockwise and counterclockwise directions around the Z axis under the direction of CAD/CAM controller 101. The drive mechanism 110-1, in various other embodiments, may also be configured to raise and lower the turn-table 110 in the +Z and the −Z directions under the direction of CAD/CAM controller 101. In various other embodiments, the drive mechanism 110-1 may also be configured to move the turn-table 110 in the +X direction, the −X direction, the +Y direction the −Y direction, or any combination thereof.

The one or more robotic arms 121 may be configured to place the dispensing end of the extrusion needle 123 at any location in the build volume of object 151, from any approach angle. This enables manufacturing system 100 to lay fiber strands on the inside an enclosure such as a closed sphere through a hole in the enclosure (e.g., sphere) just large enough for extrusion needle 123. The robotic arms 121, in various embodiments, may be powered by electric motors, hydraulic actuators, or combinations thereof, and configured to provide three or more axes or degrees of freedom so that the extrusion head/needle can move in the +X direction, the −X direction, the +Y direction, the −Y direction, the +Z direction, the −Z direction, or any combination thereof. In one illustrative embodiment, the robotic arm 121 may be configured as a six-axis robotic arm. In another illustrative embodiment, the robotic arm 121 may be configured as a seven-axis robotic arm. Any other suitable positioning assembly capable of placing the dispensing end of the extrusion needle 123 at any location in the build volume of object 151, from any approach angle, may be used in place of the robotic arms 121.

The extrusion head 122 is configured to melt the thermoplastic and extrude the molten thermoplastic (which may partially or wholly contain one or more fiber strands) via the extrusion needle 123. Various embodiments of the extrusion head 122 may define an interior chamber 122-1 for receiving the thermoplastic material. The extrusion head 122 may include a heater or heating element 122-2 for melting the thermoplastic material within the chamber for extrusion through the extrusion needle in liquid form. The extrusion head 122 may include a motor (not shown) or any other suitable mechanism for pushing the thermoplastic material through the chamber 122-2 and out the extrusion needle 123. In some embodiments, the extrusion head 122 may also be configured with a cutting mechanism 122-4 to cut the one or more fiber strands to the appropriate length. The cutting mechanism 122-4 may include a blade or other suitable cutting member for cutting the one or more fiber strands. In one illustrative embodiment, the cutting mechanism 122-4 may be disposed at the dispensing end or tip 123-1 of extrusion needle 123.

Extrusion needle 123 may comprise a hollow tube or nozzle having a first open end that communicates with the chamber of the extrusion head 122 and a second open end (dispending end or tip 123-1) that dispenses the thermoplastic, which may partially or wholly contain one or more fiber strands. The opening of the tip 123-1 may be circular, oval, square, slotted or any other suitable shape that is capable of extruding the thermoplastic material in a desired cross-sectional shape. In various embodiments, the extrusion needle 123 may have a length equal to at least the longest dimension of object 151 so that the tip of 123-1 extrusion needle 123 can deposit material at any location in the build volume of object 151 from any approach angle.

In operation, according to one illustrative embodiment, one or more motors may be used for feeding the filament(s) of thermoplastic material 131-1, 131-2 (and fiber strand(s) 131-3) into the chamber 122-1 of the extrusion head 122 from the spools 130-1, 130-2, 130-3. The thermoplastic material entering the chamber 122-1 is melted by the heater 122-2, and extruded from the extrusion head 122 via the extrusion needle 123. The CAD/CAM controller 101 may control the rate of the one or more feed motors, the temperature of the heater 122-2, and/or the other process parameters mentioned earlier, so that the thermoplastic material and fiber strand(s) can be extruded in a manner that to attempts to satisfy the desired structural properties of object 151.

Although the manufacturing system, methods, thermoplastic filaments, fiber strands, and other associated elements have been described in terms of exemplary embodiments, they are not limited thereto. Rather, the appended claims should be construed broadly to include other variants and embodiments of same, which may be made by those skilled in the art without departing from the scope and range of equivalents of the device, tray and their elements. 

What is claimed is:
 1. An apparatus for manufacturing an object, the apparatus comprising an extrusion head for extruding thermoplastic material associated with one or more fiber strands.
 2. The apparatus of claim 1, further comprising a spooled filament of thermoplastic material for feeding to the extrusion head, the filament of thermoplastic material containing one or more fiber strands.
 3. The apparatus of claim 1, further comprising a spooled filament of thermoplastic material for feeding to the extrusion head.
 4. The apparatus of claim 1, further comprising a spooled fiber strand for feeding to the extrusion head.
 5. The apparatus of claim 1, wherein the extrusion head includes an extrusion needle through which the thermoplastic material and the associated one or more fiber strands are extruded from the extrusion head.
 6. The apparatus of claim 5, wherein the extrusion needle has a length equal to at least the longest dimension of the object.
 7. The apparatus of claim 1, wherein the extrusion head includes a blade element for cutting the one or more fiber strands.
 8. The apparatus of claim 7, wherein the extrusion head includes an extrusion needle and wherein the blade element is disposed at a dispensing tip of the extrusion needle.
 9. The apparatus of claim 1, wherein the extrusion head includes an extrusion needle and further comprising a positioning assembly for placing a dispensing tip of the extrusion needle at any location in a build volume of the object from any approach angle.
 10. The apparatus of claim 9, wherein the positioning assembly provides at least three degrees of freedom.
 11. The apparatus of claim 9, wherein the positioning assembly comprises a six or seven axes robotic arm.
 12. The apparatus of claim 9, wherein the extrusion head moves along a Z axis in any direction, along an X axis in any direction, along the a Y axis in any direction, and any combination thereof.
 13. The apparatus of claim 12, further comprising a controller for directing at least one of the positioning assembly and the extrusion head.
 14. The apparatus of claim 9, further comprising a controller for directing at least one of the positioning assembly and the extrusion head.
 15. The apparatus of claim 1, further comprising a platform on which the object is built.
 16. The apparatus of claim 15, wherein the platform includes a drive mechanism for rotating the platform around a Z axis in any direction, moving the platform along the Z axis in any direction, moving the platform along an X axis in any direction, moving the platform along a Y axis in any direction, or any combination thereof.
 17. The apparatus of claim 16, further comprising a controller for directing the drive mechanism.
 18. The apparatus of claim 1, further comprising a controller for: generating a design for the object that substantially satisfies desired structural properties of the object; generating a sequence for extruding the thermoplastic material and the associated one or more fiber strands to manufacture the object according to the design; and directing the extrusion head to extrude the thermoplastic material and the associated one or more fiber strands according to the sequence.
 19. The apparatus of claim 18, wherein the controller includes a list of structural properties of the thermoplastic material and the associated one or more fiber strands, the list being used by the controller for generating the design and the sequence.
 20. A method for manufacturing an object, the method comprising: generating, in a computer process, a design for the object that substantially satisfies desired structural properties of the object; generating, in a computer process, a sequence for extruding one or more beads of thermoplastic material to manufacture the object according to the design, wherein the one or more beads of thermoplastic material are associated with one or more fiber strands; and extruding the one or more beads of thermoplastic material and the associated one or more fiber strands according to the sequence.
 21. The method of claim 20, wherein the one or more fiber strands are disposed within the one or more beads, partially within the one or more beads, adjacent to the one or more beads, or any combination thereof.
 22. The method of claim 20, wherein the one or more fiber strands and the one or more beads are extruded together or separately in any order.
 23. The method of claim 20, wherein the length of any of the one or more fiber strands is short, medium, or long.
 24. The method of claim 20, wherein the one or more fiber strands are made of the same material or different materials or some of the one or more fiber strands are made of the same material and some of the one or more fiber strands are made of different materials.
 25. The method of claim 20, wherein the one or more fiber strands have the same modulus of elasticity or different modulus of elasticity, or some of the one or more fiber strands have the same modulus of elasticity and some of the one or more fiber strands have different modulus of elasticity.
 26. The method of claim 20, wherein at least one of the one or more fiber strands comprises a bundle of fiber strands.
 27. The method of claim 20, wherein the one or more fiber strands are oriented parallel to a longitudinal axis of the one or more beads, at an angle to the longitudinal axis of the one or more beads, or parallel to a longitudinal axis of the one or more beads and at an angle to the longitudinal axis of the one or more beads.
 28. The method of claim 20, wherein the one or more fiber strands are cut to a desired length in accordance with the design prior to being extruded, after being extruded, or prior to being extruded and after being extruded.
 29. The method of claim 20, wherein the extruding step is performed with an extrusion head, and wherein after the sequence generating step and prior to the extruding step, further comprising feeding one or more filaments of the thermoplastic material to the extrusion head to be melted therein, wherein the one or more beads of the thermoplastic material are extruded from the melted filaments of the thermoplastic material.
 30. The method of claim 29, wherein at least one of the one or more filaments of the thermoplastic material includes at least one of the one or more fiber strands.
 31. The method of claim 29, further comprising feeding at least one of the one or more fiber strands to the extrusion head and associating the at least one of the one or more fiber strands with the one or more beads of the thermoplastic material.
 32. The method of claim 31, wherein at least one of the one or more filaments of the thermoplastic material includes at least another one of the one or more fiber strands.
 33. The method of claim 20, wherein the extruding step is performed with an extrusion head, and further comprising moving the extrusion head along a Z axis in any direction, along an X axis in any direction; along a Y axis in any direction; or any combination thereof, as the sequence progresses.
 34. The method of claim 20, wherein the extruding step is performed on a platform, and further comprising rotating the platform around a Z axis in any direction or along the Z axis in any direction, or any combination thereof, as the sequence progresses.
 35. The method of claim 20, wherein the extruding step is performed on a platform with an extrusion head, and further comprising moving the extrusion head along the a axis in any direction, moving the extrusion head along an X axis in any direction, moving the extrusion head along a Y axis in any direction, rotating the platform around the Z axis in any direction, moving the platform along the Z axis in any direction, or any combination thereof, as the sequence progresses. 